In the competitive world of electronics, companies are continually taken to task to ensure that the products they sell are of the utmost reliability and quality. A company must test its products to determine the quality of the product at any point in the design and manufacture process. In the field of microelectronics, for example, such testing requires more advanced techniques to ensure the viability of high-speed microelectronics circuits and devices.
Techniques for testing semiconductor switches, such as conventional bipolar transistors, may involve testing the switching characteristics of the transistor. These transistors are commonly used as binary switches having only two states, on and off. For example, a threshold voltage is applied to the base of the switch to determine whether the collector-emitter gate opens (i.e., whether the transistor switches on). If the transistor does not switch to on, then it is considered defective and is not used. Also, once the threshold voltage is removed or if the voltage applied to the base falls below the threshold voltage, the collector-emitter gate should close (i.e., the transistor should switch off). If the transistor does not switch on, or does not switch off then it is considered defective and is not used.
More recent semiconductor designs involve devices that have more than just an on state and an off state. Hewlett-Packard has developed the memristor, short for memory-resistor, which is a nano-scale semiconductor device that is nonvolatile and has more than just on and off states. The memristor has intermediate states that are achieved by applying a predetermined voltage or current to the device to change the resistance of the device. The intermediate states are various resistive states of the device. Furthermore, if the predetermined voltage or current is removed, the intermediate state is maintained, hence its non-volatility. Because of the memristors characteristics, such as the intermediate states and non-volatility, conventional testing techniques for testing the on/off state of conventional transistors do not work for testing memristors. However, if mass produced, the memristors will need to be tested for quality assurance.